Typewriter



Oct. 12, 1943. A. s. DENNIS TYPEWRITER Filed Dec'. 30, 1941 3 Sheets-Sheet l INVENTOR 400/p/2u5 .5. flan/W's ATTORNEY Oct. 12, 1943. A. s. DENNIS TYPEWRITER Filed Dec. 30, 1941 3 Sheets-Sheet 2 m m hwnhiw INVENTOR Ado/p/ws 5. Den/7L5 ATTORNEY Oct. 12, 1943.

A. s. DENNIS TYIEWRITER Filed Dec. 30, 1941 5 Sheets-Sheet 3 R & QTQ

5 Wm m & Q .fi! & [by R MN I. w M M r|\ 1' w. 6 w NM 1 Q m Q Q. \N a l R R R. Q Q U, I. N u QR Lw 1 mm 2. R. v. mm R Q NM R m muwlnfi BY 44 [Q ATTORNEY Patentedoet. 12 194? UNITED s'mrss- PATENT oFFicc Adolphus S. Dennis, Oakland, C'aliL, assignor to Friden Calculating Machine Co'., Inc., a corporation of California App ication December-'30, 1941, Serial No. 424,960

.10 Claims. (01. 197-17) This invention relates to typewriters and isconcerned more particularly with the provision of power operation of the type bars thereof.

' It is a general object of the invention to provide an improved power-operated drive for the key bars of typewriters.

Another object of the invention is to provide power-driven mechanism of the character referred to which can be readily applied to existing typewriters. I Other objects and advantages of the invention will be apparent from the following description of a preferred embodiment thereof, as illustrated v in the accompanying drawings, in which:

. Figure l is a longitudinal sectional view showdriven as indicate dby the adjacent arrows, the

drive being constant when the motor is energized under con 01 of its switch 3|.

The co tantly rotating rolls 26 are used to driveoa series of normally expanded, but collapsible elements, each element forming part of a drive unit for an associated dummy key bar l6 as will ing the power drive mechanism as applied to a typewriter.

Figure 2 is a fragmentary elevational section of a unit of the power drive mechanism as positioned in Figure 1.

Figure 3 is a view similar to Figure 2 but showing the parts in position at the beginning of the downstroke of the key.

Figure 4 is a view similar to Figures-2 and 3 The frame of the typewriter is indicated at |0, while the platen is shown-at II, this platen being now be described.

Referring to Figure 1, each dummy key bar I6 is similar in construction to the rearward end of conventional key bars of the typewriter, and

as each of these dummy key bars and, in fact, the key drive unit for each of the-typewriterkeys, is similar, only one will be described. Each key bar 16 is; guided adjacent its forward end in a comb 32 suitably secured to a cross bar 33 of the typewriter frame. Adjacent its rearward end the keybar I6 has a releasable; pivotal connection at 34 with a cross rod against which it is urged by a spring 36. The spring 36 maintains the for ward end of the key bar l6 against a rubber bumper bar 31 having a yieldable mounting by means of one or more springs36 below the cross bar 33 of the frame. 1 j

Referring to Figure 2,'the key bar I6 is provided with a vertically extending slot 4| which is enposed plunger or auxiliary key stem 43. Stem" gaged by a stud 42 mounted in a vertically disand key bar I6 are connected by a tension spring 44. The lower end of stem 43 is provided with a round extension 46 guided in a suitable aperture in a crossbar 41. Intermediate. its ends the stem 43 is provided with .a slot 5| which is engaged by a pin 52 carried by a key stem or bar 53 which has a releasable pivotal connection with a cross stud 54 (Figure 1) and is spring-urged in a clock wise direction by spring 56. The key stem 53 mounted in the usual fashion on the traveling paper carriage, part of which is shown at l2. The conventional form of type bar is indicated at l3 which is operated through a linkage "from a dummy key bar or steml6 referred to in greater detail hereinafter. The linkage I4 is also connected in a conventional manner to the usual escapement operating mechanism II. This escapement nechanismis also operable through a space bar l8 of the usual character.

As shown, the typewriter I6 is suitably secured upon a base 2! which houses the power driven mechanism. The power driven mechanism includes a motor 22 which is suitably mounted in the base 2| andis connected by reducing gearing 23 to similar meshing gears 24. for a pair of rubber covered'drive rolls 26 secured on respective shafts 21. The shafts 21 are suitably journaled at their ends in respective removable brackets28, each bracket being secured to a similar supporting plate 29. suitably mounted on a wall of the casing 2|. Itwill beseen that the rolls26 are extends upwardly and through a guide comb 6'l to provide a key 56 of the typewriter keyboard.

Downward movement of key stems 53 is limited by means of a transverse stop bar53 (Figure 1) suitably secured at its ends on the base 2|.

. previously explained, the auxiliary key stem 43 (Figure 2) forms part of a normally expanded but collapsible means for drive by the rollers 26. For this purpose the key stem has I pivoted thereon at 6! a normally expanded arm .62 having a tapered lower end 63 normally spaced from a flange 64 secured on the stem 43. The position of the expansion arm 62 is controlled by a cam 66 pivoted-at 61 on the key'stem 43. Cam 66 is normally urged in a clockwise direction as viewed in Figure 2 by a spring 68 to cause contact of the. stop surface 69 of the cam 'with a stop pin H on the key stem 43. Spring 68-15 tensioned between a pin on the cam 66 and the tail of a latching pawl 12 whichis pivoted at 13 on the key stem 43. Pawl 12* has a pin and slot connection at 14 withthe link bar 16.

I6 pivoted at 11- on the key Normally, the cam St is positioned as shown in Figure 2 with a full arcuate surface 8| thereof engaging the expansion arm 62- to holdit outwardly in expanded position against stop pin 82.

In this position. the spacing between the arm 62 and the key stem flange 84 is wider than the spacing between the rolls 26.

Figure 3illustrates the condition of distance to move the pin 42 to the bottom of the 7 slot I and slightly tensionthe spring 44. This movement is suflicient to engage the tapered lower end 83 of arm 82 with the adjacent roll 26 while the flange is engaged with the opposite roller 28 so that the downward drive of the auxiliary key 43 of the key drive unit is begun.

Figur 4 illustrates the condition of the parts when the auxiliary key 43 has reached the botthe parts when thekey 53 has been depressed a sufficient alignment of its arcuate recess 84' with the adja- .'cent roll 28 and also interrupts the drive for the key drive unit by aligning the flat 85 of the cam 86 with the expansion arm '82 so that it can collapse. At the same time the latch 12 can become active to hold the ,cam 88 in the position shown in Figure 6 until return of. the key drive unit to its upper inactive position. At this time the rebound ofthe dummy key bar I 6 from its resilient tom of its stroke. The downward movement of the key drive unit is stopped when an arcuate surface 83 of the cam 66 has engaged the cooperating roll 26 so that the cam 65 is in driving relation with such roll. With this condition of the-parts, the cam 68.is driven in a counterclockwise direction as viewed in Figure 4 from the position shown in Figure 4 to that shown in Figure 5 where an arcuate recess 84 of cam 68 is in registry with the roll 26 and the movement of the cam is stopped by engagement of shoulder .85 thereof with stop. pin ll. During this movement a flat 88 on the cam 68 has come into cooperative relation with the expansion arm 62 to allow it. to be retracted inwardly by the adj acent roller 28 so that there: is a slight clearance between the collapsed elements'of the plunger and the driving rollsii and the drive will cease. At the same time the cam 6i has been driven slightly beyond the point where the latch 12 can move into active position.

Figure 6 shows he parts; as the return to top position has started under the influence of spring 88 (Figure 1'). At this time cam 56 has been returned clockwise by spring 68 until its shoulder it engages the latching face of pawl 12 to hold .the cam 66 in position'where flat 86 engages arm 62 to maintain the collapsedcondition of the key drive'unit so long as the key 58 is maintained depressed. Upon release of the key 58, its sprin 58 (Figure 1) becomes active to restore the parts to thecondition shown in Figure 2. The rebound ofthe dummykey bar l8 from the bumper,

3'! is suilicient to act through the link ii to disengage the latch pawl 12 from the shoulder of the cam and enable the cam 86 to turn under the influence of its spring to the position shown in Figure 2. This operation again moves arm 62 outwardly and provides an expanded condition of the key drive unit.

Briefly the operation of the power drive unit for the typewriter keys 58 is as follows: when the that shown in Figure (where the surface 83 of ca 88 engages the roll 26 and is driven thereby "from the position shown in Figure 4 to the P sition'shown in Figure 5. This movement of the cam 8t interrupts drive of the cam 88 by the stop 31 will operate through the link I6 to release the latch 12 so that the spring 68 can return-the parts from the position shown in Figure 6 to that shown Figure 2.

' I claim:

1. In a power drive mechanism for a typewriter having a typebar, an operating bar operatively connected to said typebar to effect typing movement thereof, a drive unit connected to said op erating bar, a pair of'spaced-apart drive rolls for operating said drive unit, means for driving said .rollsto cause adjacent surfaces thereof .to travel downwardly, said drive unit comprising a plunger having a normally expanded, collapsible portion with a dimension when expanded greater than the spacing between said. rolls, and said dimension being smaller than said spacing in the collapsed condition of said plunger, said portion being normally out of operative engagement with said rolls, and a key bar for moving said plunger to place said portion in driving relation with said rolls.

2. In a power drive mechanism for a type writer having a typebar. a drive unit having a drive connection with said typebar, a pair of spaced-apart drive rolls for operating said drive unit, means for driving said roll to cause adjacent surfaces thereof to travel downwardly, said drive unit comprising a plunger having a normally expanded, collapsible portion with a dimension when expanded greater than the spacing between said rolls, and said dimension being smaller than, said spacing in the collapsed condition of said plunger, said portion being normally out of operative engagement with saidrolls, and a key bar for moving said plungerto place said portion indriving relation with said rolls.

3. In a power drive mechanism for a typeriter having a typebar, a drive unit having a ive connection with'said typebar, a pair of spaced-apart drive rolls for operating said drive unit, means for driving said rolls to cause adjacent surfaces thereof. to travel downwardly, said drive unit. comprising a plunger having a normally expanded, collapsible portion with a dimension when expanded greater than the spacing between said rolls, and said dimension being smaller than said spacing in the collapsed condition of said plunger, said portion being normally out of operative engagement with said rolls, means for moving said plunger to place said portion in driving relation with said rolls, and means carried by saidplunger and operable by one of. said rolls for causing collapsing of said portion near the end of the stroke of said plunger,

4. In a power drive mechanism for a type- --writer having a typebar, a drive unit having a connection with said typebar, a pair of spacedapart drive rolls for operating said drive unit, means for driving said rolls to cause adjacent surfaces thereof totravel downwardly, said drive unit comprising a plunger having a normally expanded,-collapsib1e portion with a dimension when expanded greater than the spacing between said rolls, andsaid dime ion being smaller than said spacing in the colla ed condition of said v plunger, said portion being normally out of operative engagement with said rolls, and a key bar for moving said plunger to place said portion in driving reiation'with said rolls, said key bar having a lost motion connection with said plunger to provide for independent movement of said plunger by said rolls after initial movement of said plunger by said key bar into engagement with said rolls.

5. In a power drive mechanism for a typewriter having a typebar, a drive unit having a drive connection with said typebar, a pair of spaced-apart drive rolls for operating said drive unit, means for driving said rolls, to cause ad-' jacent surfaces thereof to travel downwardly, said drive unit comprising a plunger having a normally expanded, collapsible portion with a.

dimension when expanded greater than the spacing between said rolls, and said dimension bein smaller than said spacing in the collapsed con 6. In a power drive mechanism for a type-' writer having a typebar, an operating bar operatively connected to said typebar to effect typing movement thereof, a drive unit connected to said operating bar, a pair of spaced-apart drive rolls for operating said drive unit, means for drivin said rolls to cause adjacent surfaces thereof to travel downwardly, said drive unit comprising a plunger having a normally expanded, collapsible portion with a dimension when expanded greater than the spacing between said rolls, and said dimension being smaller than said spacing in the collapsed condition of said plunger, said portion being normally out of operative engagement with said rolls, and a key bar for moving said plunger to place said plunger portion in driving relation with said rolls. said plunger having alost motion connection with said operating bar whereby said operating bar does not move during said initial movement of said plunger by said key bar, said key bar having a lost motion connection with said plunger to provide for independent movement of said plunger by said rolls after initial movement of said plunger by said key bar into engagement with said rolls.

7. In a power drive mechanism for a typewriter having a typebar, a driveunit for said typebar, a pair of spaced-apart drive rolls for arm movably mounted on said plunger for engagement with the other of said rolls and nor mally spaced from the same, and a cam on said plunger for controlling the position of said expanding arm relative to said plunger, said cam having a portion for holding said expanding arm outwardly and a second portion to allow said arm to collapse toward'said surface.

8. In a power drive mechanism for a typegagement with the other of said rolls and normally spaced from the same, a cam on said plunger for controlling the position of said expanding arm relative to said plunger, said cam having a position for holding said expanding. arm outwardly and a second position to allow said arm to collapse toward said surface, and said cam being adapted to engage a roll at the bottom of the plunger stroke to be driven from said one position to said second position.

9. In a power drive mechanism for a typewriter having a typebar, a drive unit for said K typebar, a pair of spaced-apart drive rolls for operating'said drive unit, means for driving said rolls to cause adjacent surfaces thereof to travel downwardly, said drive unit comprising a plunger extending between said rolls and having a sur-- face for engaging one of said rolls, an expanding arm movably mounted on said plunger for engagement with the other of said rolls and normally spaced from the same, a cam on said plunger for controlling the position of said expanding arm relative to said plunger, said cam having a position for holding said expanding arm outwardly and a second position to allow said arm to recede toward said'surface, and said cam being adapted to engage a roll at the bottom of the plunger stroke to be driven from said one posi-' tion to said second position, a latch for holding said cam in said second position, and means for causing release of said latch upon return of said drive unit to inactive position.

10. In a power drive mechanism for a typewriter having a typebar, an operating bar operatively connected to said typebar to eifect typing movement thereof, a drive unit connected to said operating bar, a pair of spaced-apart drive rolls for operating said drive unit, means for driving said rolls to cause adjacent surfaces thereof to travel downwardly, said drive unit comprising a plunger extending between said rolls and having a surface for engaging one of said rolls, an expanding arm movably mounted on said plunger for engagement with the other of said rolls and normally spaced'from the same, a cam on said plunger for controlling the position of said ex panding arm relative to said plunger, said cam having a position for holding said expanding arm outwardly and a second position to allow said arm to recede toward said surface, and said cam being adapted to engage a roll at the bottom of the plunger stroke to be driven from said one position to said second position, a latch for holdsaid latch to an inactive position thereof upon return of said operating. bar into engagement with said stop. I

ADOLPHUS S. DENNIS. 

